Flashcards in General Deck (61):
Inhibits IL-2 from T cells-inhibits proliferation
AIDs defining illness
CD4 200-Toxoplasmosis and cryptosporidium
C.Diff causing antibiotics
CA-125: Ovarian epithelial
CA-19-9: Pancreatic Ca and colon
AFP: liver and yolk sac and testicular teratoma
CEA: Colon and head and neck
HCG: Ovarian, testicular teratoma and seminoma
Non-competitive aldosterone antagonist at the distal convoluted tubule-potassium sparing
2mg/kg max safe dose
0.25% contains 2.5mg/ml
therefore safe dose in 70kg (140mg/2.5)=56mls
with adrenaline 3mg/kg
without adrenaline 7mg/kg
Prilocaine-least toxic and greatest therapeutic index
6mg/ml safest dose
Thiopentone sodium: anaphylaxis, bronchospasm and hypotension
Etomidate: Less myocardial depression
Propofol: Care in patients with hypovolaemia
Halothane: Respiratory depression and negative inotrope
malignant hyperthermia (not in NO)
nausea and vomiting
Vomiting is a complex physiological process that initiates repetitive active contraction of the diaphragm and abdominal muscles to generate a pressure gradient that leads to the forceful expulsion of gastric contents. Nausea and vomiting are primarily controlled by the vomiting centre, which receives input from: (i) the chemoreceptor trigger zone (located in the area postrema of the medulla, on the lateral walls of the fourth ventricle outside the blood–brain barrier); (ii) visceral afferents from the gastrointestinal tract, which relay information to the brain regarding gastrointestinal distension and mucosal irritation; (iii) visceral afferents from outside the gastrointestinal tract (bile ducts, peritoneum, heart and a variety of other organs) (stimulation of such afferents helps explain how ‘non-gastrointestinal’ pathology may result in vomiting); and (iv) afferents from extramedullary centres in the brain may be stimulated by certain central stimuli (eg odours, fear), vestibular disturbances (motion sickness) and cerebral trauma. Specific receptors that may be targeted include dopamine (D2), serotonin (5-HT3), histamine (H1) and muscarinic (M1) receptors in the area postrema, H1 and M1 receptors in the labyrinths, and 5-HT3 receptors on peripheral afferents. Many of the anti-emetic drugs act at the level of the chemoreceptor trigger zone. The main classes of anti-emetic agents include: anti-histamine and anti-cholinergic agents, dopamine and serotonin antagonists, and phenothiazines.
Phenothiazine compounds, such as prochlorperazine, appear to act primarily through a central anti-dopaminergic mechanism in the chemoreceptor trigger zone. They are of considerable value in the prophylaxis and treatment of post-operative nausea and vomiting, as well as that associated with diffuse neoplastic disease and radiation sickness. Severe dystonic reactions, neuroleptic malignant syndrome and blood dyscrasias are recognised complications. By contrast, benzamide agents, such as metoclopramide, act as dopamine antagonists, not only centrally but also peripherally. In addition, they exert a prokinetic effect on the upper gastrointestinal tract that contributes to their anti-emetic action
serotonin based antiemetics
Serotonin antagonists have recently been added to the list of clinically effective anti-emetic agents. Specific 5-HT3 antagonists such as ondansetron and granisetron have been developed, and appear to act peripherally (on peripheral afferents) and centrally (on the area postrema). They are particularly useful in the treatment of post-operative and post-chemotherapy nausea and vomiting, where they have been most effective compared to placebo and other agents in large randomised trials. The only other class of anti-emetic that acts both peripherally and centrally is the benzamides, but the benzamides do not exert their peripheral effects on afferent neurones, and have a prokinetic effect, differentiating them from the serotonin antagonists
Suture materials can be classified in three main ways:1 Absorbable or non-absorbable2 Monofilament versus braided3 Natural or synthetic.They are also categorised by size.These qualities confer different properties upon the material. Absorbable sutures give less wound support but also less foreign body reaction than non-absorbable. Monofilaments are less traumatic to tissue but are less easy to handle than braided sutures. Synthetic materials cause less tissue reaction than sutures derived from natural fibres and have generally therefore superseded them
PDSPDS is an absorbable, synthetic monofilament of polydioxanone. It has ideal qualities for use in mass tissue closure, particularly of the abdominal wall. This is because it is predictable and has high tensile strength. It is quoted that PDS retains up to 70% strength at 2 weeks and 50% strength at 4 weeks. It is then completely absorbed in 180–210 days by hydrolysis. Although many surgeons may choose to use nylon for mass closure the attendant risks of sinus formation or stitch extrusion, because of nylon’s non-absorbable properties, render this less suitable for such closure. For mass abdominal closure remember the ‘four to one’ rule. The length of suture used should be four times the length of the wound you are closing. Bites should be taken 1–2 cm apart, and 1–2 cm away from the wound edge to give good closure.
Closure of a cardiac sternotomy wound.
M – Steel wireSteel wire is the material of choice in the closure of sternotomy wounds. It has very high tensile strength and is inert. It may be monofilament or braided and can be very difficult to handle as it kinks easily. It can break and cause pain from sharp ends in the longer term.
J – ProleneProlene (polypropylene) is a non-absorbable, synthetic monofilament material that is the ideal suture for vascular anastomoses. It is inert, therefore causing minimal tissue reaction, and exerts minimal tissue friction on passage through the vascular endothelium. Braided nonabsorbable sutures can also be used, eg Ethibond. This material has an outer layer of polyester to render it smooth, and hence less traumatic to the arterial wall. Use the finest suture strong enough for the job: as a rough guide, 3/0 for the aorta, 4/0 for the iliac arteries, 5/0 for the femoral arteries, 6/0 for the popliteal artery and 7/0 for the tibial arteries are appropriate strengths.
prolene is an excellent choice when siting the polypropylene mesh used in inguinal hernia repairs. Its persistence allows for good positional maintenance of the mesh as patients begin to mobilise in the post-operative period.
AP resection position
Lloyd DaviesThe patient lies supine on the table, with legs in supports that flex the hips and knees to 45°. The legs can then be separated to allow surgical access to both abdomen and perineum at the same time (as is required during an abdomino-perineal excision of the rectum). To access the pelvis the patient is often also tilted head down, ie Trendelenberg. The lithotomy position is a more exaggerated version of the Lloyd Davies, where hips and knees are flexed to 90°. The lithotomy position was named after the operation that it was historically invented for; the removal of bladder stones. ‘Cutting for stone’ or lithotomy (lithos = stone) was frequently performed by travelling surgeons before the advent of anaesthesia and antisepsis (or fellowships).
A 42-year-old woman undergoing long saphenous vein high ligation, stripping and avulsions.
J – TrendelenbergIn the Trendelenberg position the patient is placed supine, with head-down tilt. This is the most appropriate patient placement for varicose vein surgery as it helps to alleviate pressure in the lower limb venous system and hence decreases intra-operative blood loss. This position can be also be used during laparoscopic pelvic surgery (eg gynaecological intervention, inguinal hernia repair, rectopexy) to keep bowel loops out of the operating field. The reverse Trendelenberg, as it is logically described, adopts a headup tilt. It is good for use in laparoscopic cholecystectomy/Nissen’s fundoplication, where the abdominal contents need to fall away from the region of intervention.
right nephrectomy-patient table position
Lateral decubitusIn the lateral decubitus position the patient is positioned on the contralateral side to their pathology, and the table is flexed in the centre. This stretches the flank of the patient that is uppermost, ie the side of the renal tumour. In this way there is better exposure of the loin between the bony prominences of the ribs and the iliac crest, clearly improving access and operating manoeuvrability.
arthroscopic rotator cuff
A – ArmchairThe seated armchair position is ideal for access to the shoulder, particularly in arthroscopic cases where dependency of the upper limb opens the subacromial space. This allows for easier insertion of scope and instruments. In difficult cases it also permits a longitudinal or transverse incision through the deltoid to more fully open up the shoulder joint.
Type II Error: In hypothesis testing: the term used to describe a situation in which we fail to reject the null hypothesis when a difference is really present.
Think false positive (T1) False negative (T2)
Type II errorThis is the definition of a term used in the context of hypothesis testing. A type I error in contrast is one in which we reject the null hypothesis when a real difference is not present. These terms are most commonly cited in the context of study design where the probability of type I and II errors can be reduced by performing a prior power analysis in which the correct sample size is estimated on the basis of setting a and ß values which represent the probabilities that a type II and type I error will be committed. NB the null hypothesis is the cornerstone of hypotheticodeductive reasoning (Karl Popper) not a term describing a negative approach to research!
An erroneous influence potentially effecting the conclusions of a trial caused by systematic differences in withdrawals from the trial.: exclusion bias
Exclusion biasThis is one of the four components of systematic bias (the others are in the list) that should be eliminated/minimised by good trial design and conduct. So-called ‘drop outs’ or exclusions from trials can occur for many reasons and can introduce bias quite easily since the tendency (even unintentially) is to exclude participants to favour the outcome of the trial. Where exclusions occur, this problem can be reduced by analysis on an ‘intention to treat’ basis (ie they are still included in the analysis).
minimisation: A method of allocation in comparative studies that provides treatment groups that are very closely similar for several variables.
MinimisationThis is an alternative to simple randomisation (the commonest method used to reduce selection bias) when this might potentially introduce large differences in the characteristics of comparison groups within a trial. Other methods include stratified randomisation but this is usually used for single binary variables such as sex.
M – Pasteurella multocidaPasteurella multocida is a Gram-negative parvobacterium. It is a common pathogen, found in the majority of animal bites. Other less common organisms include Staphylococcus aureus, Streptococcus pyogenes, Eikenella corrodens and other anaerobes that are commensal in animal mouths. Human mouths contain an even wider range of organisms.Treatment will therefore need to cover all of these pathogens and could typically include augmentin or an oral cephalosporin with metronidazole on an empirical basis until results of the swab are known.
Tuberculosis (TB) is caused by an aerobic bacillus (Mycobacterium tuberculosis), which has a waxy coat that appears red with acid-fast stains. It is distinctive from other granulomatous diseases, such as sarcoidosis, by its necrotising (caseating) granulomatous tissue response. Transmission, via inhalation of infected droplets, results in Primary Pulmonary Tuberculosis or a Ghon complex. This consists of a Ghon focus in the lung periphery with an associated draining lymph node that may be asymptomatic. Reactivated, or Secondary, Pulmonary Tuberculosis, results in an active infection typically in the apex of the lung, known as an Assman lesion. Either stage can progress to form tuberculous bronchopneumonia or spread more distally to a number of organs, causing miliary tuberculosis.
Scrofula (cervico-facial TB)Scrofula is common in undiagnosed, neglected cases of TB, and patients present with multiple, tender, matted, posterior or supra-clavicular lymph nodes that lie deep to the deep fascia. These may begin to point through the deep fascia into the subcutaneous plane resulting in a ‘collar-stud’ abscess, so named because of the two adjacent abscesses that communicate via a narrow tract. The overlying skin temperature is normal because the caseating process is slow, so there is little or no hyperaemia, resulting in a ‘cold abscess’.
Ethylene oxideSterilisation is described as the complete destruction of all viable microorganisms. Heat-sensitive equipment, sutures and other single-use items are prepared using ethylene dioxide as part of an industrial process. The gas is toxic but effective at killing vegetative spores, bacteria and viruses.
GlutaraldehydeJoseph Lister pioneered the concept of antisepsis in 1867 while he was Professor of Surgery at the Glasgow Royal Infirmary. He was able to reduce post-operative infections with the use of carbolic acid spray. Modern day antiseptic techniques have now moved on but the essential principles are the same. Disinfection is defined as a reduction in the number of viable organisms and is synonymous with antisepsis except that disinfectants are used in non-living tissue. Glutaraldehyde is rapidly active against bacteria and viruses including hepatitis B virus and human immunodeficiency virus but is less effective against spores and Mycobacterium tuberculosis. However, steam with formaldehyde (another more toxic aldehyde) can be used as a method of sterilisation.
AutoclaveAutoclaving is a sterilisation technique that uses saturated steam at high pressure and kills all organisms including heat-resistant spores, Mycobacterium tuberculosis and viruses. The holding time describes the minimum amount of time at a set temperature that guarantees sterility. The Bowie–Dick test is the colour change seen on a strip of heat-sensitive tape (diagonally-striped) attached to wrapped instruments that monitors steam penetration associated with the sterilisation process. Each use of the autoclave is documented in a printout that is, however, the only absolute method of guaranteeing sterility.
DobutamineDobutamine stimulates both ß1- and ß2-receptors. Stimulation of ß1-receptors produces a good cardiac inotropic and chronotropic response, leading to improved cardiac output, and stimulation of ß2-receptors produces a degree of vasodilatation, especially in skeletal muscle (‘inodilatation’). Dobutamine can be used in combination with noradrenaline if sepsis and hypotension are a problem. Studies have demonstrated that dobutamine is more effective than dopamine (dosage-dependent roles, for example at low doses it is a D1A-agonist, at intermediate doses ß1-adrenoreceptor effects appear, and at high doses a1-effects predominate) when improvements in oxygen delivery [D(O2)] and uptake [V(O2)] are considered.
Amrinone (and enoximone) are phosphodiesterase III inhibitors that increase intracellular cyclic AMP. They improve hypotension, principally caused by cardiogenic shock, by their dual action of increasing cardiac output and decreasing systemic vascular resistance (‘inodilatation’). The addition of dobutamine is considered to be synergistic.
NoradrenalineNoradrenaline stimulates a1-adrenoreceptors with minor ß1- and ß2-effects. It is employed conventionally when increased systemic vascular resistance (to increase the blood pressure by increasing left ventricular after-load) is required to maintain the mean arterial pressure after fluid replacement and dobutamine infusion have proved inadequate. This is commonly the case in septic shock where inflammatory mediator activation causes systemic vasodilatation.
A 55-year-old woman with rheumatoid arthritis presents to The Emergency Department minors department with a 48-h history of progressively worsening pain that radiates to her jaw and florid erythema to her right eye. She complains of constant watering but has not noticed any discharge. On examination she has a localised area of inflammation that is extremely tender to pressure. The injected vessels are in the deep layer of the eye.
K – ScleritisThe sclera and episclera can both become inflamed in autoimmune conditions, particularly rheumatoid arthritis. Unlike conjunctivitis, inflammation of these layers of the eye produces a localised region of injection. The distinction between episcleritis and scleritis is related to severity of symptoms and potential complications. Scleritis is characteristically much more painful than episcleritis, and the signs of inflammation are more extensive. It may ultimately result in ocular perforation. All patients require opthalmological review, and steroid eye drops will provide symptomatic relief and hasten recovery.
acute angle glaucoma
A – Acute closed-angle glaucomaThis scenario depicts a typical presentation of acute closed-angle glaucoma. This includes the rapid onset of pain, characteristically in the evening, when the pupil becomes semi-dilated (light intensity decreases). Prior episodes that have been relieved by sleep, when the pupil constricts, are also distinctive in this disease. In acute closed-angle glaucoma apposition of the lens to the back of the iris prevents the flow of aqueous from the posterior chamber to the anterior chamber. Accumulation of aqueous behind the iris pushes it forwards on to the trabecular meshwork, preventing normal drainage of aqueous from the eye. This causes an acute rise in intraocular pressure, requiring emergency intervention to preserve sight. Acetazolamide given intravenously and pilocarpine eye drops should be rapidly administered until definitive surgical/laser decompression can be achieved.
HyphaemaBlood in the anterior chamber of the eye is known as a hyphaema. Commonly resulting from blunt trauma to the globe, this must be treated as an emergency as further bleeding may increase intraocular pressure and compromise sight. Other important sequelae of blunt ocular trauma are also demonstrated in this case. When the eye itself absorbs impact, transmitted forces to the orbit can result in a ‘blow-out’ fracture, particularly of the thin orbital floor. Clues to such an occurrence include diplopia, defective eye movements (related to inferior rectus muscle prolapse through the fracture site), emphysema (fracture through a sinus) and recession of the eye (enophthalmus).
Carotid endarterectomy is indicated for patients with a symptomatic (ie transient ischaemic attack [TIA] or amaurosis fugax) > 70% stenosis of an internal carotid artery. With regard to asymptomatic but significant internal carotid artery stenosis, a recent randomised trial has shown that surgery will reduce the risk of stroke from around 12% to 6% over a 5-year period. Most surgeons would therefore not operate on patients with asymptomatic stenosis who are 80 years of age or older. Carotid stenting is still an experimental procedure and its use is confined to randomised clinical trials; previous series have shown an unacceptably high stroke rate with carotid stenting compared with surgery.
Amaurosis fugax due to which side of brain being affected?
It is important to remember that amaurosis fugax (transient, sudden loss of vision) should occur on the same side as the significantly diseased artery, whilst sensory or motor loss in the limbs should occur contralateral to the diseased artery.
Pyoderma gangrenosum (PG) are recurring nodulopustular ulcers commonly affecting the legs, abdomen and face. They are tender and have a red or blue overhanging necrotic edge. They heal with cribriform scars. Over 50% of patients with PG have associated underlying active or quiescent systemic disease – such as inflammatory bowel disease, seronegative rheumatoid arthritis, a lymphoproliferative disease, autoimmune hepatitis or Wegener’s granulomatosis. The diagnosis of PG is primarily clinical and by exclusion of other causes of cutaneous ulcerations with a similar appearance; skin histology may help. Treatment is usually with immunosuppressants and corticosteroids.
Venous ulcers may develop spontaneously or following minor trauma. There may be a history of varicose veins, deep venous thrombosis, chronic venous insufficiency, poor calf-muscle function or arteriovenous fistulae. Other factors predisposing to venous ulceration include obesity, all risk factors for deep-vein thrombosis, a family history of varicose veins and a history of leg fracture. In long-term venous insufficiency, the skin undergoes changes (atrophy and variable pigmentation), with the dermis and subcutaneous tissue becoming indurated and fibrosed; this is termed lipodermatosclerosis. Venous eczema (erythema, scaling, weeping and itching) is a common feature associated with such ulceration; this is distinct from cellulitis. The ankle–brachial pressure indices are normal in patients with classic venous ulceration.
Colonic malignancy is the second most common cause of cancer deaths in the UK. Predisposing factors include neoplastic polyps, ulcerative colitis, familial polyposis and a positive family history. Clinical presentation depends on the site: left-sided colonic carcinoma presents with abdominal pain (relieved by passing flatus), abdominal distension, per-rectal bleeding, altered bowel habits and tenesmus; a mass may be felt on per-rectal examination. In right-sided tumours, the patient may present with symptoms of anaemia from occult bleeding. Sometimes the patient complains of pain in the right iliac fossa and per-abdominal examination may reveal a mass over this region.
Crohn’s disease is common in North America and Northern Europe. Unlike ulcerative colitis, Crohn’s disease affects the whole of the gastrointestinal tract (including ulcers in the mouth). Risk factors include a strong positive family history, various types of food, smoking (increases the risk by three fold), and infective agents such as mycobacterium and cell-wall-deficient organisms such as pseudomonas. Acute Crohn’s disease may simulate acute appendicitis but is usually preceded by diarrhoea. In chronic Crohn’s disease, mild diarrhoea is experienced over many months, accompanied by intestinal colic; intermittent fevers, secondary anaemia and weight loss are also common. With progression of the disease, adhesions, transmural fissures, intra-abdominal abscesses and fistulous tracts may develop.
Ectopic pregnancy occurs in less than 1% of pregnancies. The typical history of ectopic pregnancy is one or two missed menstrual periods with other signs of pregnancy (mastalgia, morning sickness and increased urinary frequency). In ruptured ectopic pregnancy, the abdominal pain is initially crampy, but subsequently becomes a more continuous and generalised lower abdominal pain. Irritation of the diaphragm may lead to shoulder-tip pain. There may be signs of hypotension and hypovolaemic shock. Per-abdominal examination may reveal guarding, rigidity and rebound tenderness. Frequently, altered blood may be seen in the cervix and movement of the cervix produces abdominal discomfort. In some instances, a mass may be felt in one of the adenexae and the uterus is frequently soft and bulky. Ruptured ectopic pregnancy warrants immediate surgical intervention.
Although any of the three anterior abdominal aortic branches (coeliac, superior and inferior mesenteric vessels) may occlude, it is the occlusion of the superior mesenteric artery (SMA) that commonly causes mesenteric infarction. Despite the presence of collateral vessels of the SMA, these may not be able to dilate sufficiently and swiftly to overcome the acute reduction in blood flow. The occlusion may be due to a thrombus or an embolus and is seen in elderly patients who are in atrial fibrillation. Other less common causes of infarction include dissecting aneurysm and vasculitis. Clinical features include persistent, severe and generalised abdominal pain. The inflammatory markers may be elevated and the blood gas may reveal a metabolic acidosis. This condition is a surgical emergency, as the patient rapidly becomes toxic and may die from septic shock unless the infarcted bowel (‘dead gut’) is removed.
Radial nerve palsy
In low radial nerve lesions, ie those due to fractures or dislocations at the elbow, the posterior interosseus nerve may be injured and the patient is unable to perform finger extension with weakness of thumb abduction and extension.In high lesions with fractures of the humerus or due to prolonged tourniquet pressure, there is weakness of the radial extensors of the wrist and numbness over the anatomical snuffbox. In very high lesions, the radial nerve may be compressed in the axilla, eg crutch palsy.
A 25-year-old man presenting with weakness of the wrist and hand with paralysis of the triceps muscle and an absent triceps reflex.
A 25-year-old man presenting with a wrist drop with inability to extend the metacarpophalangeal joints together with paraesthesia of the skin over the anatomical snuffbox.
Fracture of the mid-humerus
A 25-year-old man presenting with failure of extension of the metacarpophalangeal joints with weakness of thumb abduction and interphalangeal extension.
Compression at the elbow
resectionSurgical resection will not cure Crohn’s disease and is usually performed for complications. The overall strategy is to be as conservative as possible to preserve functional gut length. Indications for surgery include recurrent intestinal obstruction, intestinal fistulae, fulminant colitis, malignant change and peri-anal disease. The whole of the gastrointestinal tract should be examined prior to undertaking any resection either pre-operatively or at laparotomy. Proximal small bowel strictures can be treated with segmental resection if only isolated areas are affected, or alternatively, with stricturoplasty of multiple involved segments. A right hemicolectomy involves taking the ileocolic, right colic and right branch of middle colic vessels resulting in loss of more bowel than for an ileocolic resection. Here only the Ileocolic vessels are taken. For first presentation crohns, the best treatment option is an Ileocolic resection. For fibrous crohn’s strictures, strictureplasty would be a good option.
Total mesorectal excision (TME)
Total mesorectal excision (TME)This is the operation of choice for middle and lower third tumours of the rectum that are amenable to resection without recourse to abdominoperineal excision of rectum (APER). The operation, championed by Bill Heald, attends to the main cause of local failure (recurrence) of cancer by addressing both the circumferential resection margins as well as the distal resection margin. APER is used when an adequate distal resection margin is not achievable by abdominal approach – usually because the tumour has invaded the sphincters.
Upper GI laparotomy indications (III)
D – Emergency laparotomyUncontrollable bleeding at endoscopy is one of the indications for surgery in upper gastrointestinal haemorrhage. Other indications (in most units) include:
patient > 55 years with three bleeds or more
patient > 60 years with two or more bleeds
transfusion requirement of six or more units
visible arterial spurter in base of ulcer at endoscopy.
Ruptured ectopic pregnancy
Ruptured ectopic pregnancy‘Every woman of child-bearing age is pregnant until proven otherwise.’ The typical history is of abdominal pain associated with fainting or collapse. Symptoms and signs of shock are usually present and, in the case of intraperitoneal rupture, diaphragmatic irritation gives referred pain to the shoulder. There may be a history of a missed menstrual period, but symptoms of tubal pregnancy may occur before this occurs. It is unusual for a tubal pregnancy to advance beyond 6–8 weeks without symptoms. There is usually a degree of abdominal distension and sub-umbilical tenderness and guarding. A urinary or serum ß-human chorionic gonadotrophin measurement aids in the diagnosis. Prompt treatment is important and includes resuscitation followed by urgent laparoscopy or laparotomy depending on the availability of trained staff.
Ovarian cyst torsion
K – Torsion ovarian cystThe history of sudden onset of pain without gastrointestinal disturbance suggests this diagnosis, which is a common differential in young women. The diagnosis can usually be confirmed by pelvic or transvaginal ultrasound examination, and commonly requires surgery. A similar presentation is seen with haemorrhage into and rupture of an ovarian cyst.
Maydl’s hernia is a complication of large hernial sacs, especially right scrotal hernias in Africans. It is characterised by a W-loop of small bowel lying in the sac, with strangulation of the ‘intervening’ loop within the main abdominal cavity by the constriction of the neck of the sac. The description of the operative findings differentiates this hernia from afferent loop strangulation (afferent loop entwined about afferent and efferent loops), a Richter’s hernia (part of the bowel at the anti-mesenteric margin becomes strangulated), and a Littre’s hernia (strangulation of a Meckel’s diverticulum). The operative findings also differentiate from ‘simple’ strangulation, which is associated with a similar clinical presentation, ie evidence of gut ischaemia (severe pain with systemic upset, eg fever, tachycardia) and obstruction (vomiting, and abdominal pain and distension).
Obturator hernias are six times more common in women than men, and three times more common after the age of 50 years. A preoperative diagnosis is rarely made, because a swelling is not always palpable in the thigh. Therefore, it is usually diagnosed during laparotomy for nonresolving small bowel obstruction, as in the case described. Consequently, the operative mortality is approximately 30%.
The peritoneum protrudes through
- The obturator canal
- Then between the pectineus and abductor longus muscles
- to finally enter the femoral triangle.
The Howship–Romberg sign of pain referred along the geniculate branch of the obturator nerve to the inner aspect of the knee should raise the suspicion of an obturator hernia. Other examples of hernias frequently only discovered during laparotomy for relief of intestinal obstruction include: gluteal and sciatic hernias (protruding through the greater and lesser sciatic notches, respectively), pelvic hernias (of the pouch of Douglas into the posterior wall of the vagina or vulva; not rectocoele or cystocoele, which are false hernias), and pudendal hernias (lateral protrusion of peritoneum through a persistent hiatus of Schwalbe between the origin of the levator ani from the obturator internus, usually following surgical removal of pelvic organs).
Incarcerated herniaThis question draws the candidates’ attention to the clinical differentiation of complications of hernias. Incarceration refers to fixation of contents within the hernia sac as a result of adhesions. Such a hernia is irreducible, but is neither tender, nor associated with systemic upset (differentiating it from a strangulated hernia), nor associated with gastrointestinal symptoms (differentiating it from an obstructed hernia).
Femoral hernia repair
McEvedie’s approach (or modification)The patient has an obstructed, strangulated femoral hernia. There are three approaches to femoral hernia repair and although opinion varies, the safest surgical approach (after resuscitation) in this patient (with the expectation of bowel injury and resection) is a modified McEvedie using an incision resembling half of a Pfannenstiel incision (the original McEvedie had a vertical incision necessitating division of the inguinal ligament). The preperitoneal space is tracked downwards and the hernia is opened. If a bowel resection is required a laparotomy can easily be performed either through this incision or by its extension to a full Pfannenstiel. If strangulation was not expected then the low crural approach (basically a small incision over the lump) is preferred. The high crural approach disrupts the posterior wall of the inguinal canal and has fallen from favour (in some textbooks).
inguinal hernia repair
Lichtenstein repair Based on relative ease of procedure and low recurrence rate, this repair using a polypropelene mesh is now recommended (including by the Royal College of Surgeons) as the mainstay of primary hernia repair (replacing Shouldice which was probably slightly more complex to perform adequately in most hands but still has its proponents). The recurrence rate should be
hernia in child
HerniotomyHerniorrhaphies, ie repair of the retaining wall, are not required for infantile/childhood inguinal hernias where the cause is patency of the processus vaginalis. The sac is identified and carefully dissected from the cord, its contents are emptied and the sac is then ligated and excised. This should be delayed (but only briefly) if the incarceration can be managed initially conservatively as in this case.
Psoas abscessAlthough this mass could be attributed to lymphadenopathy (probably secondary to his clear history of tuberculosis), the fluctuant nature and the presence of ipsilateral hip pain point more readily to symptoms of a psoas abscess. Psoas abscesses develop either from infection of unknown origin or as a consequence of infection spreading from an adjacent organ. The risk factors for primary psoas abscess are not known; however, trauma to the muscle may be an important factor in 18–20% of cases. Low socioeconomic class and poor nutrition have also been cited as possible predisposing factors. A major risk factor for secondary psoas abscess is gastrointestinal pathology (inflammatory bowel disease, appendicitis, diverticulitis, bowel cancer and Crohn’s disease), and the source is a gastrointestinal infection in 80% of individuals. Prior to modern anti-tuberculous therapy, psoas abscesses occurred in up to 20% of patients with spinal tuberculosis. Treatment is now usually (initially at least) by percutaneous drainage under ultrasound or computed tomography guidance.